Method of inspecting a semiconductor substrate

Abstract

A semiconductor substrate inspection system includes an e-beam inspection system configured to deliver electrons to a specimen semiconductor substrate. A sensor is configured to detect reflected electrons that reflect off the surface of the specimen semiconductor substrate. An analysis unit is configured to determine a number of electrons received by the semiconductor substrate, and to determine at least one target region including at least one defect of the semiconductor substrate. A reference image module is in electrical communication with the analysis unit. The reference image module is configured to generate a first digital image having a plurality of pixels, and to adjust a gray-scale level of the pixels included in the target region based on the number electrons included in each pixel to generate a second digital image that excludes the at least one defect.

What is claimed is: 
     
       1. A method of inspecting a semiconductor substrate, the method comprising:
 delivering a beam of electrons to the semiconductor substrate and generating a first image having a plurality of pixels based on electrons emitted from the semiconductor substrate; 
 determining a number of electrons emitted by the semiconductor substrate; 
 determining at least one target region including at least one defect of the semiconductor substrate; and 
 adjusting a gray-scale level of the pixels included in the target region based on the number of received electrons to generate a second image that excludes the at least one defect. 
 
     
     
       2. The method of  claim 1 , further comprising comparing the second image to a defect image generated in response to inspecting a specimen semiconductor substrate to determine at least one defect of the specimen semiconductor substrate. 
     
     
       3. The method of  claim 2 , wherein the adjusting a gray scale further comprises:
 determining at least one gray-scale value based on the number of electrons corresponding to each pixel; and 
 mapping the gray-scale value to each pixel included in the target region. 
 
     
     
       4. The method of  claim 3 , further comprising generating a look-up table including a plurality of electron values indicating a number of electrons included in a pixel, each electron value cross-referenced with a respective gray-scale value that adjusts a gray-scale level. 
     
     
       5. The method of  claim 4 , wherein the at least one gray-scale value includes a plurality of gray-scale values, each gray-scale value corresponding to a respective pixel included in the target region. 
     
     
       6. The method of  claim 3 , wherein the at least one gray-scale value is a median gray-scale value corresponding to the target region. 
     
     
       7. The method of  claim 3 , wherein a gray-scale level of each pixel included in the target region is adjusted to have a percentile value.